It has been difficult in the past to obtain uncontaminated bacteriological specimens from the lower respiratory track and other locations of the human body. There is a real need to be able to obtain ready access to lower airways to obtain specimens for culturing and determination of bacterial types. Fiber optic bronchoscopes are known for use in viewing of the lower airways of the lung, but sample collection through bronchoscopes often result in contamination of specimens taken, unless extraordinary precautions are taken.
In the past is has been proposed to use a single lumen catheter passed through the neck to the lower airways in transtracheal aspiration. Suction could then be applied to take a biological sample and the catheter withdrawn. This technique is often painful to the patient and requires a neck incision with problems of locating the catheter unless a bronchoscope is used.
In still another proposed method, a cytology brush is carried in a catheter plugged with a gel foam material to prevent contamination of the brush during introduction into the lower airway. The brush is then used to remove the plug and take a sample. The plug can cause a health problem when left in the lung. This method has not been found to be as effective as desired in that contamination by bacteria during passage through the upper respiratory areas can occur.
Sampling catheters of various types are found in the following U.S. patents and perhaps others: U.S. Pat. Nos.
2,767,703
2,839,049
2,955,591
3,613,664
3,800,781
3,877,464
3,881,464
4,023,559.